Process of reducing paper-stock to pulp.



No. 797,970. PATEMBD AUG. 22, 19.05. F. P. MILLER.

PROCESS OF REDUCING PAPER STOCK T0 PU LP.

APPLICATION rum) MAR. 13. 1902:.

1 UNITED STATES PATENT QFFICE.

FRANK Pe -MILLER, OF DOWNINGTOWN, PENNSYLVANIA.

PROCESS OF REDUCING PAPER-STOCK TO PULP.

Specification of Letters Patent.

Patented Aug. 22, 1905.

Application filed March 13, 1902- Serial No. 98,011.

To all whmn it may concern:

Beit known that I, FRANK P. MILLER, a citizen of the United States, anda resident of Downingtown, Pennsylvania, have invented certainImprovements in the Process of Reducing Paper-Stock to Pulp, of whichthe following is a specification.

The object of my invention is to reduce paper-stock and separate theground stock from material in circulation without interrupting the flowof the said material, so that the finished stock'can be carried from themachine and new stock added for making the process continuous.

In the accompanying drawings, Figure 1 is a longitudinal sectional Viewof an improved beating-engine used in carrying out my process. Fig. 2 isa section on the line 2 2, Fig. 1, with the shaking mechanism for thescreen removed, and Fig. 3 is an enlarged view of a portion of Fig. 1,showing the screen in detail.

A is the vat, separated by the usual midfeather a, forming two channelsthrough which the paper-pulp is traversed. In one of these channels is abeating-roll B, mounted on a shaft B, carried by suitable bearings andhaving knives 6.

C C are knives mounted in the frame of the machine, between which andthe beating-roll the pulp is passed.

A is the back-fall over which the pulp is carried by the beating-roll B,and directly back of the back-fall is ascreen D. This screen issuspended from a shake-frame D, which can be constructed in any suitablemanner, and any means may be provided for shaking the frame, so as toagitate the screen. The screen in the present instance is made up of anumber of plates, each plate being recessed on each side to form narrowslots, so that when the plates are assembled they form narrow slots forthe passage of the pulp, as shown in Fig. 2. This screen may beperforated with circular holes or slots of any shape, and the slots maybe formed in any manner. The perforations are of such size as to allowthe finished product of the machine to readily pass through the plateinto the chest E, which is directly under the screen and from which theproduct is withdrawn, either by gravity or by means of a pump throughthe outlet-passage e.

Beyond the screen D is a continuation A of the back-fall A. Theunfinished product passes over the screen and over the back-fall andcirculates through the channels, to be acted upon again by thebeating-roll. In the present instance the screen D is arranged on anincline from the back-fall A, so that the unfinished material will morereadily pass over it; but it will be understood that it may behorizontal or at any incline desired, depending greatly upon thematerial being treated.

When certain classes of paper-stock are being treated, particularly oldpaper, cardboard, books, 860., I provide means for catching the stringsand like material, and this means consists in the present instance of atransverse shaft F, having a number of curved forks f arranged directlyback of the screen D and in the present instance having their tipsresting upon the upper portion of the continuation A of the back-fall.These forks are so arranged that the ordinary stock will pass betweenthem, while the strings and similar material will be caught by theforks, and when these strings accumulate the operator simply turns ashaft F and raises the forks and removes the strings, which can eitherbe collected for other paper-stock or reduced in another machine. Theshaft F in the present instance is suspended from a shaft F by arms f,and this shaft is operated by a lever f so that the shaft F and itsforks can be moved out of the way when desired.

While any suitable means may be provided to shake the screen D, in thepresent instance I have shown one form of shaking means which I will nowproceed to describe.

Mounted on pedestals K K on each side of the vat are spring members ish, from which is suspended by bars 7. the screen D.

I is a driven shaft having cams a thereon, which act against plates '6,carried by the spring memberslsis. The shaft I is mounted in suitablebearings, and the shaft may be driven from the beater-shaft B, ifdesired, or it may be independently driven.

The back-fall A may be provided with a yielding lip a, which willoverlap the frame of the screen D, so as to prevent the material fromentering the chest E except through the screen. A like lip 60 may beprovided at the opposite end of the screen, which will overlap theportion A of the back-fall, Fig. 3.

The material to be reduced into paper-pulp is placed in a vat with asuflicient amount of water. The beating-drum is set in motion,

The material is reduced by passing between the beating-roll and knivesuntil it is in condition to be removed from the engine.

In its passage through the vat the material passes over my improvedscreen, and there is sufiicient suction caused by the agitation of thescreen to draw certain particles of the material through the screen.These particles are those that have been reduced to the desiredcondition, and they pass into the chamber under the screen and are drawnout through any suitable pipe connected with any suction device, eithergravity or pump, as desired. The balance of the stock circulates throughthe vat, passing under the roll until it is finally reduced to thedesired condition, when it will pass through the screen into the chamberE. This processiscontinuous, and new stock can be added without stoppingthe machine. In fact, after the machine is once charged with paper-stockthe finished stock can be removed and additional stock added.

By my improved apparatus, which forms the subject of a separateapplication, Serial No. 110,523, filed June 6, 1902, the rags, strings,and similar material can be collected by the forks placed directly backof the screen, while wires, nails, and other heavy foreign matter willcollect in the bottom of the vat, and pockets m may be provided for thispur pose.

My invention is especially adapted for grinding and reducing old paperand paper-stock; but it will be understood that it may be used inconnection with any material which can be ground to a pulp to formpaper.

In reducing some classes of paper-stock it has been the practice to workthe beating-engine until all the stock is reduced to such a consistencythan it can be transferred to a paper-making machine. It has been foundin reducing the paper-stock in this manner that a great portion of/thematerial was reduced to such an extent that the fiber was destroyed, andconsequently the paper which was made from the pulp was not strong. Thisis entirely obviated by my invention, and the pulp as soon as it is incondition to be removed from the machine passes through the screen andaway from the pulping mechanism. The machine can be either used as acontinuous machine or as an intermittently-operating machine, accordingto the desire of the operator.

I claim as my invention 1. The process herein described of reducingpaperstock to pulp, said process consisting in continuously circulatingthe stock, heating it during such circulation, positively grading thecoarse and fine stock during the circulation, and withdrawing the finestock from the circulation without interrupting the uniform flow of thecoarser stock, substantially as specified.

2. The process herein described of reducing paper-stock to pulp, saidprocess consisting in continuously circulating the stock, heating itduring such circulation, positively grading the coarse and fine stockduring the circulation, and withdrawing the fine stock from thecirculation by suction without interrupting the uniform flow of thecoarser stock,substantially as specified.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRANK P. MILLER.

Witnesses:

WILL. A. BARR, Jos. H. KLEIN.

